The batteries on board should be checked for adequate operational conditions and maintained if required. The Interval for inspections and maintenance of the batteries and connected system is decided as per Safety Management System and manufacturers’ requirements.
Most generic items for maintenance are:
- Batteries on board should be regularly checked and maintained as per Safety Management System and manufacturer’s requirements.
- Maintenance should include checking the battery installation and charging rectifier, ensuring the batteries are in full charge condition, and filling them with distilled water as needed.
- Battery tops should be clean and dry, terminal nuts should be tight, and a smear of petroleum jelly should be applied to prevent corrosion.

- Electrolyte levels should be checked and maintained at the proper level with the correct value of specific gravity using a hydrometer.
- Metal tools used for maintenance should be plastic coated to prevent short circuits.
- To know if a battery is fully charged, the electrolyte-specific gravity can be measured with a hydrometer.
- A fully charged battery has a specific gravity of about 1.27-1.285 (hydrometer scale 1270 to 1285).
- A fully discharged battery will have a specific gravity of 1.1 (1100)